1. Field of the Invention
The present invention relates to an apparatus and method for cleaning a drive member and also a read and/or write head of a machine, such as a tape drive, which is adapted to operate on a tape cassette containing a magnetic tape.
2. Background Art
There are various machines which operate to receive information from, or impart information to, magnetic tape. Two such commonly used machines are video player/recorder units and audio player/recorder units. In the video units, the magnetic tape is pulled outwardly from a cassette tape cartridge and brought into engagement with a shallow cylindrical surface of a rotating element on which the player/recorder head is carried. In the audio unit, the magnetic tape generally extends across a forward portion of the tape cassette, with the tape being exposed at this forward portion. The tape passes by a stationary player/recorder head, and is also engaged by a capstan and pinch roller of the machine to cause the tape to move along its length.
Various cleaning devices have been proposed to clean the operating surfaces of such player/recorder units. With the video unit, it has been a common practice to provide a cleaning ribbon which is engaged by guide elements in the video player/recorder unit to carry the cleaning ribbon into engagement with the rotating element carrying the playing/recording head and possibly into engagement with other components of the video player/recorder unit.
Another type of cleaning mechanism which is used more commonly with audio player/recorder units comprises a cassette housing which carries a cleaning member which in turn is adapted to carry a cleaning element, such as a pad. This cleaning member is arranged to move on a cleaning path, which in many cleaning devices is a back and forth path where it wipes against the playing/recording head of the audio unit. Quite commonly, the cleaning member is driven on its back and forth path through a suitable drive transmission from one of the drive spindles in the audio player/recorder unit.
To obtain the proper cleaning action, it is desirable to have adequate frictional engagement between the cleaning pad and the surface of the player/recorder head of the audio unit. However, if the force of the frictional engagement is excessive, then the resistance imparted back through the drive transmission to the drive sprocket may trigger the automatic shutoff mechanism in the machine.
Another concern is that the operating surface of the player/recorder head is quite often not a flat surface, but a moderately curved surface. Also, in some instances, the operating surface of the head may be a compound curved surface, having two side curved portions, with a moderate recess between the two curves. This may have a tendency to create a resisting force against the cleaning pad greater than that would normally be encountered simply from frictional engagement.
Another consideration is that the location of the player/recorder head will vary from machine to machine. Thus, the cleaning element (i.e. usually the cleaning pad) must be mounted in such a way that it can be positioned at different forward to rear locations and still be in proper cleaning engagement with the player/recorder head.
One common means of mounting the cleaning element is to place it on an arm which is pivotally mounted for back and forth motion about a pivot location located in the center portion of the cassette housing. To accommodate different forward to rear locations of the cleaning element, there is sometimes provided a spring arm, which in one form can be a U-shaped spring section, such as shown in U.S. Pat. No. 4,225,893--Loiselle. This same patent shows another method of accommodating this difference in forward to rear location of the cleaning element is to mount the forward to rear lever arm itself by means of a pin and slot connection so that it can be positioned at different forward to rear locations as the pivot arm swings back and forth about the pivot location to accomplish the cleaning motion.
With regard to the problem of the cleaning element being "caught" or "snagged" on the surface of the playing/recording head (e.g. possibly being engaged by a side surface portion of the head so as to create a relatively large resistance to the back and forth movement of the cleaning element), one approach to this problem, as shown in U.S. Pat. No. 4,454,551--Clausen et al, is to provide the arm which carries the cleaning pad with a spring having a somewhat "Z" configuration, where the spring has two oppositely positioned U-shaped spring sections.
In yet other instances, the cleaning element is mounted to a carrier which, instead of a pivot motion, has a linear side to side motion, with the carrier or carriage for the cleaning pad having a laterally extending member mounted between pins. An example of this is shown in U.S. Pat. No. 4,442,468--d'Alayer de Costemore d'Arc.
In addition to video and audio playing/recording units, there are also tape drives which move a magnetic tape relative to a read/write head so that data can be taken from the tape or transmitted to the tape. In one such tape drive, which is sold by Hewlett Packard as the HP 9144A Tape Drive, there is provided a read/write head which is positioned at a front side location relative to the tape cassette, and the operating surface of this head has a pair of vertically oriented ridges which protrude outwardly from the operating surface a short distance. With regard to cleaning such a read/write head, for example by a back and forth motion of a pad, these ridges aggravate the problem of the cleaning pad encountering an excessive resisting force by the pad coming into engagement with the side surfaces of these ridges.
In this tape drive machine, there is a drive wheel (i.e. a capstan) which engages a drive element in the tape cassette to cause movement of the tape. The operation of the machine is such that the motion imparted to the tape is a somewhat erratic back and forth motion.
In the parent application noted above, U.S. Ser. No. 818,120, now U.S. Pat. No. 4,816,952 there is described a cassette cleaner to clean the read/write head of the tape drive machine, such as a Hewlett Packard machine described above. There is a cassette housing having a carriage mounted for lateral back and forth movement in the housing. The carriage has a slot and pin mounting at a left forward location, and a cleaning pad at a right forward location, with a gear and cam transmission to cause the lateral back and forth motion of the carriage. Power to the gear and cam transmission is supplied by a drive wheel 78 which engages a drive capstan or roller 16 which is a component of the tape drive machine.
While the cassette cleaner described in U.S. Ser. No. 818,120 effectively accomplishes its intended function, there is still the problem of cleaning the capstan or drive roller of the tape drive machine.
A search of the U.S. Patent literature has disclosed a number of patents relating generally to devices for cleaning a capstan or similar device, and these are listed below.
U.S. Pat. No. 4,631,616 (Zago et al) shows a cleaner where there is rotatable cleaning element driven by rotation of the spindles of the machine.
U.S. Pat. No. 4,599,669 (Meermans) shows a cassette cleaner where a cleaning pad engages the capstan, and a spring device urges the cleaning pad into engagement with the capstan.
U.S. Pat. No. 4,510,545 (Boudreau) shows a capstan cleaning device in which the cleaning pad is mounted in a cassette case. There is a flexible band 12 which is manually accessible for pulling, and which has a forward portion which engages the cleaning pad. By pulling on this band 12, the cleaning pad is brought into frictional engagement with the capstan 10.
U.S. Pat. No. 4,458,281 (Kara) shows a cleaning device where there is a cassette housing which can be placed in a first position where a drive roller 57 engages the capstan so as to drive a rotatable cleaning roller 72 that in turn wipes against the playing/recording head. Then the cassette housing can be inverted so that a cleaning pad 80 is positioned against the capstan so as to clean the capstan when the capstan rotates.
U.S. Pat. No. 4,272,796 (Van Kreuningen et al) shows a cassette cleaner where there is a pad 30a which is urged against the capstan so as to clean the same.
U.S. Pat. No. 4,225,893 (Loiselle) shows a cassette cleaner where there is provided a capstan and pinch roller cleaner, in the form of a pad which is urged by a spring into cleaning engagement.
U.S. Pat. No. 4,141,053 (Kara) shows a head and capstan cleaner in which the head cleaning roller 62 is driven through gears by the capstan 16. The capstan 16 is then cleaned by causing it to be engaged with a cleaning pad 88, this being accomplished by inverting the cassette cleaner from its first position.
U.S. Pat. No. 3,761,994 (Becht) shows a cleaning device where there is a pad 34 which bears against the capstan so as to clean the same. The head is cleaned by a hand-operated pad.
U.S. Pat. No. 3,655,924 (Puskas) shows a pickup head demagnetizer. The drive capstan of the player drives a carrier on which magnets are mounted, with the carrier rotating so as to produce an alternating magnetic field to cause the demagnetization.